ON THE EARTHQUAKE AND VOLCANIC PHENOMENA OF JAPAN, 103 

 3. Area Sliaken in each Month in Square Bi. 



4. -4rea o/ Seismic Disturbances. 



The area shaken by the earthquakes varied with their intensity from 

 a mere local tract up to several thousand square ri. 1 square ri=about 5 9 

 square miles. The following table is a classification of the earthquakes 

 according to the area disturbed : — 



From the above table we see that TGI earthquakes out of the total 

 number of 930 disturbed areas less than 100 square ri, 117 areas between 

 100 and 1,000 square ri, and 46 areas greater than 1,000 square ri. We 

 may add that one earthquake shook an area of nearly 6,000 square ri, 

 whilst another shook an area of about 9,000 square ri. 



5. Intensity of Earthquakes. 



During the year 1889, as we have seen, the total number of earth- 

 quakes was 930, of which 51 were of a severe character, 290 of moderate, 

 and the remaining 589 were slight, shocks. Thus, severe ones were 

 6 per cent, of the total number of earthquakes, moderate ones 31 per cent., 

 and slight ones 63 per cent. 



Notes on Special Earthquakes. 



1. February 18, at 6h. 9m. Os. a.m., 6h. 27m. Os. a.m., 7h. 48m. 52s. 

 A.M., 8h. 2m. Os. A.M., and lOh. 10m. 56s. a.m. The first shock was the 

 strong one, shaking 5,750 square ri ; 300 square ri near Tokio, where 

 walls were cracked, tombstones overturned, clocks stopped, &c., was 

 severely disturbed. The centre appears to have been in the Bay of 

 Tokio. Earthquakes which are severe in Tokio seldom shake more than 

 one or two neighbouring provinces, and, as measured by the land area 

 which is shaken, they can only be considered as moderate disturbances. 

 This earthquake, however, was felt on the West Coast, and shook 21 

 provinces {see ninth Report, 1889). 



2. May 12, at 10.40 a.m. The shock disturbed 4,800 square ri in Centra! 

 Japan. Thirty-seven provinces were shaken, Mino and Owari, the sile of 



